I'm running BES server 4.0 with about 15 blackberries all working perfectly. One of the phones was working perfectly for a few weeks then all of a sudden stopped receiving emails.

I've deleted the user from the BES server, rebooted the server, Wiped the handheld, tried everything but still not working. We run exchange 2003 Enterprise.

Whilst upgrading from standard to enterprise exchange 2003 we moved this user's mailbox to a new information store. This is when the problem started. We moved it back but this didn't resolve the issue.